Add a views context and related sources

Ready for review

we will now support usages like this, see the tests in the MR :

   $build = [
      '#type' => 'component',
      '#component' => '...'
      '#ui_patterns' => [
        'props' => [
          'title' => ['source_id' => 'view_title'],
        ],
        'slots' => [
          'header' => ['sources' => [['source_id' => 'view_header']]],
          'exposed' => ['sources' => [['source_id' => 'view_exposed']]],
          'attachment_before' => ['sources' => [['source_id' => 'view_attachment_before']]],
          'rows' => ['sources' => [['source_id' => 'view_styled_rows']]],
          'empty' => ['sources' => [['source_id' => 'view_empty']]],
          'pager' => ['sources' => [['source_id' => 'view_pager']]],
          'attachment_after' => ['sources' => [['source_id' => 'view_attachment_after']]],
          'more' => ['sources' => [['source_id' => 'view_more']]],
          'footer' => ['sources' => [['source_id' => 'view_footer']]],
          'feed_icons' => ['sources' => [['source_id' => 'view_feed_icons']]],
        ],
      ],
      '#source_contexts' => [
        'ui_patterns_views:view' => new Context(new ContextDefinition('any'), $view),
      ],
    ];

We also introduced the component form to configure the display of a view.
The MR includes some playwright tests for that feature.

thank so veryyy much for the review, it has allowed to strengthen the code :)
it seems better now, ready for merge?

Pierre suggested we merge the two sources for raw rows and styled rows,
and provide both logics in the same class.
doable but we also provide a little evolution of RequiredArrayValuesConstraintValidator to allow a list of candidate contexts to match.
i will modify the code and push.